A corn harvester such as described in commonly owned application Ser. No. 955,181 filed Oct. 27, 1978 (now U.S. Pat. No. 4,291,521) and U.S. Pat. No. 4,206,581 strips the ears of corn off cornstalks and then comminutes these ears into fragments including pieces of corn cob, pieces of husk, and kernels. The machine then separates the kernels from the rest of the fragments, retains the kernels, and spreads the rest of the fragments over the field behind the harvester as mulch.
Obviously it is essential that a minimal amount of kernels be lost and that a minimal amount of nonkernel fragments be mixed in with the retained kernels. Hence complex riddle arrangements are provided to separate the kernels from the rest of the fragments. These systems are somewhat complex, and virtually all frequently either waste an unacceptable amount of corn kernels or retain too much nonkernel waste.
Another problem is that the husk pieces which have a low surface density--ratio of surface area to mass--often form a layer on the riddle that prevents the kernels from working their way down and through the riddle. Thus kernels that should be recovered at the riddle ride right through this part of the machine on a layer of husk pieces and are discarded therewith.
In addition it is fairly common for kernels to become stuck to pieces of husk and cob. The comminution crushes some of the kernels and thereby generates a sticky liquid that adheres many of the fragments together. As a result some kernels remain stuck to husk and cob pieces and are discarded with them.